1. Field of the Invention
The present invention relates to a drain cover assembly, more particularly to a drain cover assembly that includes a closure device for closing a drain hole in a cover plate of a drain cover unit.
2. Description of the Related Art
Referring to FIGS. 1 to 3, a conventional drain cover assembly 10 is shown to include a drain cover plate 11 that is formed with a plurality of drain holes 12, and a bottom plate 14 that is fastened to a bottom side of the cover plate 11 with the use of a fastener 13 so as to close the drain holes 12. In a normal state, by virtue of inherent resiliency of the bottom plate 14, the drain holes 12 are closed. However, when water, such as rainwater, fills the drain holes 12, the water applies a load on the bottom plate 14, which causes the latter to flex, thereby opening the drain holes 12 for draining purposes.
The following are some of the drawbacks of the aforesaid conventional drain cover assembly 10:
1. Closing and opening of the drain holes 12 is possible due to the resilient characteristics of the bottom plate 14. However, since the bottom plate 14 is likely to suffer from elastic fatigue after a period of use, the bottom plate 14 will eventually be unable to close the drain holes 12.
2. Since there is always a clearance present between the bottom plate 14 and the cover plate 1, insects cannot be prevented from passing through the drain holes 12 in the cover plate 11.
3. Dirt that accumulates between the bottom plate 14 and the cover plate 11 adjacent to the fastener 13 can affect adversely the closing effect of the bottom plate 14.